One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10,12,16,13,15,21,23)(11,17,19,24,18,14,20,22)(25,26)(27,33)(28,30)(29,37)(31,35)(32,36)(34,40)(38,39)(1,3,4,8)(2,5,6,7)(11,18)(14,17)(19,20)(22,24)(26,30)(31,39)(32,37)(33,40)(3,8)(5,7)(9,11,13,18)(10,14,15,17)(12,20,21,19)(16,24,23,22)(25,27,28,34)(26,31,30,39)(29,38,36,35)(32,40,37,33)(2,6)(5,7)(26,30)(31,39)(32,37)(33,40) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.